This invention relates to an apparatus for delivering treatment to a specific location in a portion of the body and the method of using this apparatus to achieve this treatment delivery. Specifically, this invention relates to the method, usually written in software for a computer, for controlling currents in coils, which create a force on a magnetic object to achieve this treatment delivery to the specific location in the body part.
Present methods of controlling the current in multiple-coil force mechanisms usually employ linear methods. That is, power supplies or amplifiers supplying the coil currents act in a direct or a feedback mode to cause the desired magnetic effect in response to some manner by which the effect is detected. This method is often termed the "servo amplifier" method. Two examples are the control of magnetically suspended models in wind tunnels, and the control of magnetically suspended shafts in magnetic bearings.
When the coils have large inductance, the amplifiers and/or power supplies which supply the currents must be capable of delivering large amounts of power in order to change the currents with sufficient rapidity to maintain control of the forces on the magnetic objects. Added to this is the difficulty encountered with superconducting coils, which may quench when the current is changed rapidly. Quenching is the process in a superconducting magnet by which the coil loses its superconductivity and the very rapid power increase boils out much of the liquid helium which is the cooling element of the coil. As a result, superconducting coils are seldom operated in a manner in which the current changes significantly in a short time.
A need exists for a precise control system for stereotaxis systems.